AK, Cheap, uber reliable, etc, etc. More than likely the most used assault rifle on the planet. That in an of itself should be the only needed selling point.

This is just like the fact that the weapon believed to have killed more people than any other weapon ever (including nuclear and bio/chem) is..............the solviet RPG. Did you know that a NEW RPG with your choice of any one of about 20 or so different warheads cost right around $1000 on the world market. Not bad if you have a tank/helicopter/bunker/jeep/etc removed.

Agreed that AK's win the numbers game; they are the most widely used, because of being cheap, reliable, and simple to make.

For actual quality, and combat effectiveness, the M16 or M14, probably about a toss-up. M16 more versatile, can use it for sniping to 800 yards, all the way down to CQB, and can carry more ammo. But the M14 has more oomph and a longer range.